A High-Redshift AGN Serendipitously Discovered by NuSTAR

The co-evolution of galaxies and their supermassive black holes is a key component of our understanding of galaxy evolution, but it remains unclear how tightly this co-evolution happens. We serendipitously discovered a high-redshift (z=3.895) AGN using NuSTAR which provides a unique window into this question. J131453.78+243554.1 (J1314) is bright in hard X-rays and radio wavelengths, but faint in the optical-NIR. This combination implies either an AGN with a high accretion rate or an over-massive SMBH for the stellar mass of its galaxy, catching the system in an interesting phase with respect to co-evolution. We will present new Chandra observations coupled with a multiwavelength SED analysis in which we constrain the AGN and host properties. This work was supported by Chandra Grant No. G02-21107X.